Yeah, I think you're right. It makes smoke a whole lot easier now. I have to be really careful around town now. May have to readjust the afc again.

 

So I think I have an air leak now...It loses it's prime when it sits for an hour or so. I got rid of the fuel heater portion of the strainer deal, and put a new elbow hose on. When I shut down the engine, should the fuel pressure drop slowly, or will it hold pressure? I know I should pressurize the tank, but I don't have a regulator that will go down to 5psi.

Thanks.

 

Theoretically it should hold, but I haven't ever had mine do it.

Next up. have you replaced any of the fuel lines?

Also, where do you live, rust belt?

By now, your factory rubber lines will be ready to be replaced, the problem is, it is a funky setup, with rubber at the engine, that transitions to braided steel, then has a quick disconnect to the steel likes down by the drivers feet under the cab. That hose is stupid money from Dodge, so I always just replace from there to the engine with diesel rated hose, IF there is no rust on the steel lines, which if you live in the rust belt, there always is. At that point, it is just time to run rubber all the way back to the tank. If you do this, you also should reach up from below and feel the steel lines coming out of the tank module, if you feel scale, it is time to either order up a rebuilt tank module from Dodge ( will have plastic barbs), or a Vulcan draw straw.

Do all that, and you should be good for another 15 years or so, assuming you use good diesel rated hose.

 

Live in Sunny So-Cal. No rust issues here. Had the whole fuel pickup assembly replaced about 6 or 7 years ago. It had a crack and was sucking air inside the tank.

I figured out that I did not put any thread sealant on the fitting that the elbow hose attaches to at the lift pump. Never had brass pipe threads leak before. Put some thread sealant on there and it held it's prime over night. Should be good to go.

I don't think it was the other fuel lines because I didn't have any air leak problems until I changed the lift pump. Elbow hose was super stiff, and a pain to get re-installed, so I got a new one, thinking that had to be the problem, but it wasn't.

Haven't had a chance to drive it much, but so far so good. I'll probably go ahead and replace all the suction lines for good measure, but that will have to wait until next week.

Thanks for all the help!

 

So I got a chance to drive about 50 miles today. Everything seems to be running well, but the fuel pressure is a little weird. 25psi at idle. when I take off from a stop, it will drop to around 12-13-ish, and build back up to 25. also on the highway pulling a slight grade in 5th gear, the pressure will drop to around the same. From what I've been reading, I don't want the pressure to be below 17 ever? I'm kind of leery to hook onto my race trailer and pull any grades, that trailer is way heavy. I was never worried about it until I decided to put a gauge in this thing, haha.

 

No, with a P-pump you want 22-25 at idle, and about 32-35 at speed.

Don't worry about too little, we don't have wimpy pumps.....

Anyway, sounds like either the lift pump or the overflow valve is acting up.

Easy way to rule out lift pump is to pinch off the return line at the rubber part while it is running and see if your pressure gauge doesn't spike up to about 60.

If it does, the only other item is the overflow valve, Larry B sells the torquetek for a reasonable price.

 

I've got the tork tech adjustable and a brand new pump from Larry B. I installed the OFV about a week before the new pump. I've got the OFV adjusted almost all the way in. If I go any further, when I raise the rpms (no load, in neutral) the pressure drops a little before it raises back up, so I backed it off a little. I'm just under 25 at idle now. I'm almost thinking I got a pump that's not quite up to par. It's better than the pump I replaced, though.

On another note, maybe my "El Cheapo" gauge from O'reilly reads incorrectly? And maybe my old pump was fine, just a little noisy. The new one doesn't tick like the old one.

 

Yes, I would verify your gauge before I condemned the valve or pump.

If that does prove to be accurate, give LarryB a call, not knowing how long you have had your OFV, he did have some bad ones come through TorqueTek.

I guess I would also pinch off the return line while it is running first to verify it isn't the pump.

 

Have you pulled the tank module and made sure that the screen is clean and that nothing is obstructing the pickup hole? That will give you lower pressure.

 

If the prefilter is really gunked up I always assume the tank filter is also.
May require dropping the tank and flushing it out.

 

When I cleaned the prefilter, it was pretty clean. All these issues seemed to start when I changed the lift pump. When I changed the FSS, all seemed well. Then I put the gauge on it, which led to the OFV, which is only two weeks old, which led to a new lift pump, banjo washers, elbow hose, etc.

Drove it about 400 miles over the weekend, seemed to run ok, but feels a little down on power. The truck lost it's prime over night, the first night, but on the second day it didn't.

On the plus side, I drove 418 miles, and still have barely over a half tank of fuel left. I did drive a bit slow though, following the guys with trailers...